Has anyone tried it ??
a performance report??
The old threads are a little too argumentative.
They suck for turning. Cheap molded plastic.
Sir W,
I am wondering about the “half pipe” fin. Was that the one you are referring to?
probably the ones made for noseriding
the marginal benefit of nose riding is outweighed by the marginal damage to turning.
Well there are about 45,000 turbo Tunnel users around the world. I will post some oftheir comments in the near future. And by the way GE Lexan is not a very cheap plastic. Jet canopys are made using GE Lexan and to the contrary it is a very expensive plastic.
To clarify,
This is the “fin” I was referring to;
Quote:
To clarify,
This is the “fin” I was referring to;
dlock, The Tunnel fin concept from the 60’s was designed for noseriding to the extreme. But not great at turning like Sirwanksalot states. Mahalo, Larry
Aloha dlock - looks like you’re interested in Mr. Roy Stewart’s version of the tunnel fin (thus that ala rs that I missed in the title at first glance). I’m afraid I haven’t ridden one myself so can’t really give you a ride report, but I am intrigued and would be interested in a try, just for a kick. What kind of board were you interested in trying it on? Roy was pretty into them and their supposed benefits, though most of his boards he has them on are in the rather long range - stand up, bottom turn and go. Not exactly cranking turn machines. I swear one of the long-time contributors tried making a version of it, but haven’t the foggiest where that thread might be. Perhaps you came across it already. Were you thinking glass on or plugs?
In a very informative communique from Roy himself.
There is light and life at the end of the tunnel, at least water.
Isn’t it ridiculous how few have actually tried this design.
Here is a couple of the first paragraphs:
]Cheers David,
Setting the tunnel up is easy enough, a good place to start is a tunnel
with a diameter of 4 to 8 inches, fore and aft length of 2 to 4
inches, thickness of the tunnel wall 1/4" to 3/8" , foiled either flat
on the inside or double foiled ( foiled on the inside and outside ) A
good reliable place to start is single foiled.
The tunnel should not be set up with toed in side fins, they go well
with parallel keel fins provided that the fore and aft distance between
the back of the tunnel and the leading edge of the keel isn’t too long.
. . . don’t try to make a thruster pattern out of the fins , best to
have the leading edge of the tunnel actually in between the keel fins so
that they overlap, keeping the fore and aft fin distance about 8 or 9
inches max. The nicest combination is to put the tunnel behind a single,
any single will do, keep the tunnel very close behind the single, like a
1 inch gap.
Board wise best to start with a board that has plenty of nose lift and
a flat tail rocker, longer heavier boards are easier to control the
pitch angle on, and more self tending, so they keep the tunnel working
easily, but no reason why shorter boards can’t be used we have them on
boards down to 7 feet and I know a guy who uses them on 6 footers.
The angle of the tunnel to the bottom is important, the basic method is
to get the tunnel to direct the water parallel to the bottom, that
means making the trailing edge a sixteenth or so futher from the bottom
than the leading edge if using a single foiled tunnel, and just parallel
with a double foiled one. For more excitement and more lift crank up
the lift angle by another sixteenth or so, not too much.
If you want the rest let me know.
Quote:
Quote:To clarify,
This is the “fin” I was referring to;
dlock, The Tunnel fin concept from the 60’s was designed for noseriding to the extreme. But not great at turning like Sirwanksalot states. Mahalo, Larry
dlock, I wanted to make sure my answer was applied to the proper Tunnel Fin concept, because by looking at my post with your reply showning Roy’s fin set-up, it’s not Roy’s concept I was referring to. It’s a Tunnel fin concept that a couple of my friends have from the 60’s that I was referring to. Roy’s set-up with the front fin is a newer Tunnel Fin concept that I find interesting which I believe Roy has a website showing him surfing this fin set-up. Sorry if my answer attached to your reply confused things. Have a Happy New Year! Mahalo,Larry
Hey Thanks Larry,
and Happy New Year to you as well.
In the swirling pool of information here it is easy to see a thread end up eddying out.
I will come back here and post after the New Year with an update on the fin.
Cheers.
Quote:
Well there are about 45,000 turbo Tunnel users around the world. I will post some oftheir comments in the near future. And by the way GE Lexan is not a very cheap plastic. Jet canopys are made using GE Lexan and to the contrary it is a very expensive plastic.
Greek, it is all relative.
PEEK is an expensive plastic.
PVC (plastic water pipes) and polypropylene (kitchen cutting boards) are cheap ones.
Polycarbonate is firmly in the middle, as a plastic with reasonably good mechanical properties, but not exceptional. It gets used in surfboard fins mainly for its looks - it is by far the best choice for translucent plastic fins.